QUESTION STEM:A regular hexagon has six equal sides, each of length 27.The perimeter of a polygon is the sum of...
GMAT Geometry & Trigonometry : (Geo_Trig) Questions
- A regular hexagon has six equal sides, each of length \(27\).
- The perimeter of a polygon is the sum of the lengths of its sides.
- What is the perimeter of this hexagon?
Answer Format Instructions:
Enter your answer as an integer. Do not include units.
Question Type:
Fill-in-the-blank/Grid-in
1. TRANSLATE the problem information
- Given information:
- Regular hexagon (6 equal sides)
- Each side length = 27
- Need to find perimeter
- What this tells us: We need to add up 6 sides, each with length 27
2. TRANSLATE the perimeter concept
- Perimeter = sum of all side lengths
- For equal sides: Perimeter = number of sides × length of each side
- For this hexagon: \(\mathrm{Perimeter = 6 \times 27}\)
3. SIMPLIFY the calculation
- Calculate: \(\mathrm{6 \times 27 = 162}\)
- You can verify: \(\mathrm{6 \times 20 + 6 \times 7 = 120 + 42 = 162}\)
Answer: 162
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students may forget that a hexagon has 6 sides and use the wrong number of sides in their calculation.
They might think a hexagon has 5 sides (confusing with pentagon) or 8 sides (confusing with octagon), leading to calculations like \(\mathrm{5 \times 27 = 135}\) or \(\mathrm{8 \times 27 = 216}\). This causes them to get stuck or provide an incorrect answer.
Second Most Common Error:
Poor SIMPLIFY execution: Students understand the setup correctly but make an arithmetic error when calculating \(\mathrm{6 \times 27}\).
Common mistakes include \(\mathrm{6 \times 27 = 152}\) or \(\mathrm{6 \times 27 = 172}\), leading to incorrect final answers due to computational errors rather than conceptual misunderstanding.
The Bottom Line:
This problem tests whether students can correctly identify the number of sides in a hexagon and apply the basic perimeter formula. The key insight is that "regular" means all sides are equal, so multiplication can replace repeated addition.